1. Field of Invention
This invention pertains to the protection of electrically operated devices from damaging voltage levels, particularly high voltage levels attending atmospheric disturbances such as lightning.
2. Prior Art and Other Considerations
Prudent practice suggests that electrical and electronic devices should be protected from high voltage levels lest the devices sustain inordinate if not irreparable damage. Electrical disturbances in the atmosphere have long posed perilous problems to electrical devices, and are nowadays particularly troublesome for communications and computer devices.
The conventional approach for protecting electrical devices from damaging voltage levels involves utilization of passive portection devices. These passive devices cause disconnection of the protected devices after high voltage levels or spikes are actually detected, i.e., after a storm has already reached a magnitude that can damage or destroy electrical devices. Numerous passive detectors have been employed, including metal oxide varistors, thyrectors, gas discharge tubes, and ground rods. Lacking in the prior art is a protection system that protects electrical equipment before a storm reaches a perilous magnitude.
The passive protection devices described above disconnect the protected device and keep the protected device disconnected until a human intervenes to re-connect the protected device. Sustained disconnection in his manner occasions unnecessary down time for devices which otherwise might profitably be communicating with the outside world after the threat of damaging voltage levels has subsided.
Passive protection devices cannot ascertain when, despite the threat of damaging voltage levels, the continued use of the protected device should nevertheless be accommodated. Such discretion would be particularly advantageous, for example, in the field of radio communications wherein an opportunity should be provided to continue transmissions in progress at the time of detection of the potential threat of high voltage levels.
Accordingly, it is an object of the present invention to provide method and apparatus for protecting an electrical device from a potential threat of damaging voltage levels.
An advantage of the present invention is the provision of method and apparatus which selectively disconnects and re-connects a protected a device in accordance with a sensed potential of damaging voltage levels.
A further advantage of the present invention is the provision of method and apparatus which protects an electrical device from a potential of damaging voltage levels but which also accommodates continued utilization of the device under desirable conditions.